Electrochemical Sensors Based on Au-ZnS Hybrid Nanorods with Au-Mediated Efficient Electron Relay

摘要

Development of a novel and stable electrochemical sensor electrode for the sensitive and reliable determination of p-nitrophenol (p-NP) is of great importance to environment. In the present work, electrocatalysts of Au/ZnS hybrid nanorods were prepared via a facile photoassisted reduction process for an efficient detection of p-NP. The microscopic analysis revealed the uniform adherence of Au onto ZnS nanorods. As-fabricated AZS nanorods were evaluated for the efficient sensing of p-NP by modifying a glassy carbon electrode (GCE). The cyclic voltammetry analysis revealed the unique oxidative sensing ability of AZS for p-NP at 0.14 V with a low Delta E-p (118 mV) when compared to that of bare GCE. On the basis of the notable sensing ability of AZS, a reliable and sensitive electrochemical method was anticipated for the determination of p-NP. Moreover, the effects of scan rate and pH level were examined to find out the optimized conditions at which there were a higher sensitivity and low detection limit. At optimal conditions, the p-NP oxidation current was found to follow linear relationships in the concentration range of 150-2000 nM, and the lowest detection limit for p-NP was obtained for 8AZS with a value of 320 nM and a signal-to-noise ratio of 3. The proposed electrochemical method was further evaluated in the presence of other inorganic cations and anions, and it was found that the interference was almost negligible. The real sample analyses confirmed the acceptable recovery levels.